I've got a little problem. Is it possible to add a vue scene to a contribution map?

I have a glossy object in the middle of a vue scene. I want to render out the object and the vue scene separately but in one *.exr-file for compositing purposes.

the rgba channel looks good in compositing application; I see the object and the vue scene. the object pass looks good too. but the vue scene pass comes out black, although I added the vue light to a contribution map.

is there a solution for this problem or maybe a workaround?

thank you